This invention relates to covered containers. It relates more particularly to a latch assembly for releasably retaining a cover to a container. The latch assembly is especially advantageous for use on surgical instrument sterilization trays.
A sterilization tray usually comprises a base container with an open top for holding surgical instruments or other articles. The open top of the base container may be closed by a cover which engages over the top of the container. Preferably, the cover and/or the base container are perforated so that steam can circulate through the closed container. To prevent the cover from becoming disengaged from the base container during handling, means are usually provided for releasably securing the cover to that container.
Conventionally, the securing means often consist of at least one latch which is usually mounted to one of the base container and cover and which is movable between a locked position wherein the latch engages over the other of the base container and cover, and an unlocked position wherein the latch is released from the other of the base container and cover. One such prior latch in widespread use consists of a rolled metal bracket hinged to the edge of the cover and a rolled metal hook pivotally connected to the bracket at a location thereon spaced from the bracket hinge. To lock the cover, the hook is swung down so that the hook engages a hole or projection in the base container and then the bracket is swung down to a stable over center position against the cover so that tension is applied to the hook whereupon the hook remains tightly engaged to the base container.
While that prior cover securement operates satisfactorily in many respects, it is disadvantaged in that if the closed container should be dropped onto a hard surface, the bracket may move away from it over-center position due to inertia. Resultantly, the hook member may become disengaged from the base container thereby allowing the cover to separate from the base container so that the contents of the container can spill onto the floor.
As an improvement to that over center-type latch arrangement, we developed a safety clasp assembly disclosed in U.S. Pat. No. 5,706,968. It comprises a rocker, an axle pivotally connecting the rocker to the container cover and a slider positioned between the axle and the cover. The slider is slidable along the cover in a direction perpendicular to the axle between a locked position wherein the slider interfits with the base container and an to unlocked position wherein the slider is disengaged from that container. When the slider is in its locked position, portions of the rocker and slider interfit preventing movement of the latter. In order to move the slider to its unlocked position, the rocker has to be rocked about its axle against a spring bias to disengage the rocker from the slider allowing the latter to move to be moved to its unlocked position.
While that safety clasp assembly has definite advantages over the then prior art, it also has a few drawbacks. More particularly, the container cover has to be modified to form eyes in the container cover to anchor the axle ends of each clasp assembly. Also, some people find it difficult to move simultaneously both the rocker and the slider as necessary to release the clasp using only one hand. Resultantly, some people have been reluctant to use sterilization trays incorporating such clasp assemblies.
Accordingly, it would be desirable to be able to provide securing means for reliably releasably securing a cover to a sterilization tray or other base container, which is easy to operate using only one hand, yet does not require modification of the cover or container.
Accordingly, it is an object of the present invention to provide an improved latch assembly for releasably securing a cover to a sterilization tray or other such base container.
Another object of the invention is to provide a latch assembly of this type which can be moved between its latched and unlatched positions quite easily only using one hand.
Another object of the invention is to provide such a latch assembly which is relatively easy and inexpensive to make and to assemble.
A further object of the invention is to provide a latch assembly of this general type which can be installed on a conventional cover without requiring any appreciable modification of the cover or container.
A further object of the invention is to provide a latch assembly which signals when it is in its latched and unlatched conditions.
Other objects will, in part, be obvious and will, in part, appear hereinafter.
The invention accordingly comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the following detailed description, and the scope of the invention will be indicated in the claims.
Briefly, the present latch assembly for securing a cover to a container comprises a base for mounting to the container cover adjacent to an edge thereof, a cover member secured to the base and a slider slidable along a passage between the base and cover member between a latched position wherein a portion of the slider interfits with the container and an unlatched position wherein the slider portion is disengaged from the container. A headed spring member interposed between the slider and the base resiliently interfits with holes in the slider to signal when the slider has reached its latched and unlatched positions and to releasably retain the slider at those positions.